[Two cases of Creutzfeldt-Jakob disease with high neuron-specific enolase level in cerebrospinal fluid].

Because neuron-specific enolase (NSE), one of the distal branch enzyme of Embden-Myerhof glycolytic pathway is abundant in the neuronal cytoplasm and axons, the measurement of its level in cerebrospinal fluid (CSF) would be useful in diagnosis and consideration of pathophysiology in various neurological diseases. The Creutzfeldt-Jakob disease (CJD) in which neuronal destruction is usually prominent pathologically, has so far been thought to reveal no abnormalities in CSF. In the two cases of CJD, we conducted the time sequential measurement of NSE level in CSF and compared it with serum NSE and CSF lactate levels. We found that the CSF NSE level was high in the early stage of this disease, at which time the brain CT showed no or minimal abnormalities, followed by gradual increase up to the maximum level when myoclonus and periodic synchronous discharge appeared in electroencephalogram. Then, the CSF NSE level decreased in parallel with the progression of brain atrophy in CT scan and finally on the late stage, the CSF NSE level fell within normal range. Serum NSE and CSF lactate levels were mildly elevated in all stages of this disease, but were not parallel to the disease activity. This implies that the CSF NSE level can serve as a marker for the presence of active process in neuronal destruction. Again the CSF NSE level was elevated in both cases even from the very early stage when the typical clinical manifestations of this disease were absent. Therefore, the results of this study provided us with an important indicator for the early stage diagnosis of CJD.